JL & JLU Wrangler Axle Gear Ratios: 3.45, 3.73, 4.10

RockAltered

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Wow, and people think I'm anal. So all this heavy math and we still end up waiting to see where the sweet spot is. At this point my only conclusions are still: 33's, 4:10's and .67 OD from the factory. Look for the sweet spot without lift, or gear change and hope to reach 2200 rpm at 70 and if it turns 2300+ I can have 35's.





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DanW

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Much of the data from Jeep's estimated 4 million miles of testing was to find the sweet spot for the setups they offer from the factory. 6 and 8 ratios in the transmissions give them some flexibility to make it work for both the factory setups and larger tires. The ratios in the Rubicon tell me they planned for 35s to be easy to run without regearing. I can't wait to try the manual with 33s back to back with my 08 manual Rubicon with 33s. I'll report back quickly when I do. Btw, for me, that 08 is geared just fine with the 33s and 4.10 axle ratio.
 

Afiorica21

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I am ordering a JLU sport s and want to lift about 3.5" with 35" tires on it. can anyone tell me if I should regear when I do the lift and bigger tires?
 

wishihadajeep

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I am ordering a JLU sport s and want to lift about 3.5" with 35" tires on it. can anyone tell me if I should regear when I do the lift and bigger tires?
You should be fine. The JL sports 3.45 gears with the new 8spd have a better 1st gear ratio than the JK with the 5spd and 4.10s.

JK 5spd auto 1st gear combined ratio with 4.10s is 14.72
JL 8spd auto 1st gear combined ratio with 3.45s is 16.25
 

Afiorica21

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You should be fine. The JL sports 3.45 gears with the new 8spd have a better 1st gear ratio than the JK with the 5spd and 4.10s.

JK 5spd auto 1st gear combined ratio with 4.10s is 14.72
JL 8spd auto 1st gear combined ratio with 3.45s is 16.25
I am getting it in manual. Probably should have put it in their first.
 

wishihadajeep

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I am getting it in manual. Probably should have put it in their first.
Not sure with the manual. 1st gear is lower on the new 6spd, but the rest of the ratios are higher.

JL 6spd 1st-5.13 2nd-2.63 3rd-1.54 4th-1.00 5th-0.81 6th-0.72
JK 6spd 1st-4.46 2nd-2.61 3rd-1.72 4th-1.25 5th-1.00 6th-0.79
 

GARRIGA

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You should be fine. The JL sports 3.45 gears with the new 8spd have a better 1st gear ratio than the JK with the 5spd and 4.10s.

JK 5spd auto 1st gear combined ratio with 4.10s is 14.72
JL 8spd auto 1st gear combined ratio with 3.45s is 16.25
Safe to say JLUR with 4.10s and auto should move 37s with ease and still have overdrive at 80 mph? Seen a video where Dana had there JL with 37s and the stock axles but changed to 4.88s, if I recall correctly. I'd like to stay as stock as possible for the next few years but want bigger tires.
 

AnnDee4444

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anyone have something like this for the 4cl turbo?
Not exactly, but I am able to calculate road force by gear. Let me know the specifics you want to see and I can upload a graph for you.

Here's an example:
Solid = Rubicon 2.0 with 35" tire, stock gearing
Dashed = Stock Rubicon 2.0​
Pounds of Road Force by Gear (1).png
 

kkuntz01

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This chart, while specifically applicable to the JK NOT THE JL, might help to give a general understanding of how gear ratio relates to tire size.

3.6-jkgearing.jpg
Does anyone know if a chart like this has been created for the JL?
 

Wolfy

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Anyone done a chart like this that includes the Sport 3.45 and 8 speed?
 

AnnDee4444

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